Closed chest cardiac massage apparatus



May 19, 1970 M. B. GREENLEE ETAL 3,5

CLOSED CHEST CARDIAC MASSAGE APPARATUS 3 Sheets-Sheet 1 Filed March 1,1968 VAR\ABL.E

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SOLENL'HD I32.- TO PUMP s l Tm 6M 5 I Mm Lc 0N E LE AW m FROM RES'E RVOI R TO RESE'RJ/Ql R ATTORNEY i United States Patent 3,512,522 CLOSEDCHEST CARDIAC MASSAGE APPARATUS Malcolm B. Greenlee, Rockville, andLawrence M. Mastracci, Silver Spring, Md., assignors to ResearchCorporation, New York, N .Y., a nonprofit corporation of New York FiledMar. 1, 1968, Ser. No. 709,762 Int. Cl. B01d 15/00 US. Cl. 128-53 11Claims ABSTRACT OF THE DISCLOSURE The patient is strapped on a backplate, whereupon a supporting frame is assembled and carries above thepatient an apparatus having a reciprocating stem provided with a cushionfoot at its lower end engageable with the patients chest. The shaft isreciprocated, the massage foot being moved away from the patient byfluid pressure and being moved toward the patient by predeterminedspring pressure, to bring about cardiac action.

BACKGROUND OF THE INVENTION Cardiac massage as presently used is amanual procedure, which is extremely tiring and requires the full timeand attention of trained personnel. This type of massage is highlyimportant in the event of cardiac arrest, and if promptly begun canresult in the saving of many lives.

SUMMARY OF THE INVENTION A back plate is laid in position for thestrapping thereon of a patient, either on his back or side, and in asupine but not prone position. Framing elements are then assembledrelative to the back plate and include spaced upper supporting membersfor the massage apparatus. This apparatus comprises a casing in which isarranged a cylinder having a piston therein provided with a shaftextending beyond the upper and lower ends of the cylinder. A cushionedfoot, carried by the lower end of the shaft, is adapted to press againstthe patients chest in repeated movements to stimulate the heart action.The spring urges the piston downwardly to apply pressure through thepadded foot to the patient, the loading of this spring being adjustable.A fluid, and specifically hydraulic fluid, is supplied the cylinderbeneath the piston after the latter reaches the lower limit ofmovements, to move the piston upwardly against the compression of thespring to load the latter for the following downward movement of theshaft. The supplying of the fluid to the lower end of the cylinder isaccomplished automatically so that the piston and its presser foot arereciprocated automatically.

A suitable valve mechanism, automatically controlled, alternatelysupplies to and releases pressure from the lower end of the cylinder. Areservoir and pump are employed, the valve mechanism controllingcommunication between the cylinder and reservoir and connecting theseelements on the down stroke of the piston. Such valve mechanism closesduring upward movement of the piston, and a solenoid actuated valvesupplies pumped fluid from the reservoir to the cylinder during upwardmovement of the piston. When the piston reaches its upper limit ofmovement, the valve between the cylinder and reservoir opens, and thevalve past which fluid is pumped during the upward piston stroke closesso that continuedoperation of the pump bypasses fluid to the reservoir.

To secure proper timed relation of the piston reciprocation, the pistonstops at its upper limit of movement under the control of an adjustabletimer, the operation of which after a suitable interval, for example onesecond, causes a reversal of the valve operation to release the pistonfor downward movement under the influence of the spring.

Manually operable means is provided for predetermining the minimumloading of the spring according to the age and size of the patient. Suchminimum spring force will be exerted at the end tof the downward travelof the piston unless restricted by the patients chest.

Means is also provided for adjustably limiting the upward movement ofthe piston, thus determining the distance of travel of eachreciprocation of the piston.

A manual device for actuating the piston is provided in the event of afailure of power for automatically operating the apparatus. This manualmeans may be very quickly attached and detached.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axial sectional view ofthe reciprocating mechanism and its casing, parts of the latter beingbroken away and elements of the mechanism being diagrammaticallyrepresented;

FIG. 2 is a side elevation of the apparatus including the frame forsurrounding and supporting the patient;

FIG. 3 is a plan view of the same;

FIG. 4 is a horizontal sectional view of line 44 of FIG. 2;

FIG. 5 is an enlarged fragmentary sectional view on line 55 of FIG. 4;and

FIG. 6 is a diagrammatic view of the electrical system for theapparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 2 and 3, thenumeral 10 designates a supporting frame as a whole, comprising lowerspaced parallel tubes 12 over which is mounted a back plate 14 which isadapted to the patient. End portions of the plate 14 are provided withstraps 16 for securing the back plate in position. After the back platehas been strapped in position end tubular members 18 of generallyU-shape, having upper and lower parallel ends 20 and 22, are assembledrelative to the tubes, the ends 22 being slipped into the ends of thetube 12. The upper ends 20 are then slipped into the ends of upperhorizontal tubes 24 similar to the tubes 12, the tubes 24 having mountedthereon a breast plate 26 which acts as a support for the massageapparatus indicated as a whole in FIG. 2 'by a numeral 28.

Referring to FIG. 1, the apparatus 28 comprises a casing 30 of generallyL shape (see FIG. 2) in which is arranged a cylinder 32 supported in thecasing in any suitable manner. A piston 34 is reciprocable in thecylinder 32 and is mounted on a shaft 36 which projects down wardly asubstantial distance through the lower head 38 of the cylinder. At itslower end the shaft 36 carries a ferrule 40, covered with a soft pad 42adapted to engage the chest of the patient on the backboard 14, tomassage the patients chest. The piston 34 carries a depending hub orboss 44, engageable with a spring washer 46 supported on the cylinderhead 38 to cushion downward movement of the piston as it approaches itslower limit of movement.

The cylinder 32 carries an upper head 48 and the shaft 36 projectsthrough and substantially beyond such head.

The two cylinder heads are provided respectively with a suitable bearing50 and packing 51 for the shaft 36.

A coil spring 52 has its lower end engaging the piston 34 and its upperend engaging a spring seat 54. Vertical racks 56 are secured at theirlower ends to the spring seat 54 and project upwardly through openings58 in the cylinder head 48. Above the cylinder head 48 is arranged ashaft 60 extending transversely of the cylinder and provided with apairof pinions '62 engaging the respective racks 56. Bearings 64 may beprovided on the cylinder 3 head 48 for the shaft 60. This shaft extendsthrough opposite walls of the upper portion of the casing 30, and suchwalls also preferably carry bearings 66 for the shaft 60.

One end of the shaft externally of the casing is provided with a gear 68meshing with a pinion 70 mounted on a shaft 72 supported in a bearing 74carried by the adjacent casing wall. A wheel 76, carried by the shaft72, is provided with a handle 78 for rotating the wheel and consequentlythe shaft 60 to rotate the pinions 62 and thus move the racks 56 andspring seat 54 vertically. This operation adjusts the loading of thespring 52, and the adjustment is for the minimum loading of the springwhen the piston is at its lower limit of movement. The gear 68 may besuitably graduated on its outer face, and the indicia move beneath apointer 80 carried by the casing 30.

Above the cylinder head 48, the shaft 36 is provided with a fixed collar82 engageable with the limit switch 120 to detect downward movement ofthe shaft and reinitiate the cycle. Downward movement of the piston 34is cushioned by the spring washer 46. On the upper end of the shaft 36and projecting substantially thereabove is arranged a sleeve 84, theupper end of the shaft being threaded as at 86 for adjustment of theheight of the sleeve 84 on the shaft. At its lower end, the sleeve 84 isprovided with an annular flange 88 for a purpose to be described.

The upper end of the sleeve 84 is provided with annular rack teeth 90,engageable by the teeth of a gear 92 mounted on a shaft 94 supported inopen topped bearings 96 carried by the top of the casing 30. The shaft94 is provided with a handle lever 98 carrying a spring pressed pawl 100engageable with the teeth of the gear 92 and having a finger piece 102adapted to be pressed to release the pawl 100 from the gear teeth underconditions to be described. The pawl mechanism and associated elementsis provided for the manual operation of the apparatus in the event of apower failure.

The sleeve 84 is graduated as at 104 and a cooperating index 106 carriedby the top of the casing cooperates 'with the graduations 104 toindicate the length of each piston stroke. This stroke, as furtherdescribed below, is determined by the position of the flange 88 relativeto elements with which it is associated. Obviously the sleeve 104 isrotatable to raise and lower the flange 88 with respect to the piston34.

Within and adjacent to top of the casing 30 is arranged a solenoid 108,the armature of which projects beyond opposite ends of the coil of thesolenoid and is urged to the right by a spring 109. One-end of thesolenoid rod 110 projects through the adjacent wall of the casing and isprovided with a knob 112 for the manual operation of the solenoid coilunder conditions to be described. The inner end of the solenoid rod isconnected with a pivoted latch 114 having a lower tooth 116 engageablebeneath the flange 88 when the piston reaches its upper limit ofmovement. The solenoid 108 is supported by a bracket 118, fixed at itslower end to the cylinder head 48. This bracket also supports a limitswitch 120 having an operating roller 122, engageable with the flange 82when the piston reaches its lower limit of movement.

The cylinder head 48 also carries a bracket 124 supporting at its upperend a limit switch 126 having an operating roller 128 engageable withthe flange 88, when the shaft 36 reaches tis upper limit of movement,this being the position shown in FIG. 1.

Within the casing 30 is arranged a reservoir 130 having an outlet pipe132 and an inlet pipe 134. The adjacent wall of the cylinder 32 isprovided with a port 136 controlled by a valve 138 arranged in a chamber140 communicating between the port 136 and the reservoir 130. A normallydeenergized solenoid 142, diagrammatically shown in FIG. 1, operates thevalve 138. This valve is biased to the open position shown and isadapted to be closed upon energization of solenoid 142.

Diametrically opposite to port 136 the cylinder 32 is provided with aport 144 adapted to be controlled by one end of a double-ended valve 146biased to close port 144 and adapted to open such port upon energizationof a solenoid 148. The valve 146 is arranged in a chamber 150, normallycommunicating with the line 134 leading to the reservoir. An inlet port152 leads into the chamber from a motorized pump 154 to which fluid issupplied from the reservoir through pipe line 132.

A variable timer 153 is arranged in the casing as shown in FIG. 1 and asshown diagrammatically in FIG. 6. This timer is provided with anadjusting knob 155 for varying the time interval of operation and asfurther referred to below, the timer is constantly energized andself-resetting. This is a conventional type of timer and accordinglyneed not be shown or described in detail.

The means for vertically adjusting the apparatus 28 is shown in FIGS. 4and 5. Four vertical shafts 156 are arranged at the bottom and adjacentthe corners of the casing 30. Each of these shafts (FIG. 5) projectsdownwardly through the casing 30 and through the breast plate 26 and isthreaded at its lower end as at 158 for adjustable engagement with afixed nut 160 secured beneath the breast plate 26.

Each shaft 156 carries a sprocket 162, and a chain 164 extendscontinuously around these sprockets as shown in FIG. 4. One of theshafts 156 carries a worm gear 166 engageable by worm 168 mounted on ashaft 170. This shaft is supported in a bearing 172 carried by thebottom of the casing 30 and in a bearing 174 carried by the side wall ofthe casing. A wheel 176, carried by the shaft 170, is provided with ahandle 178 whereby the shaft may be rotated. All of the shafts 156 willbe simultaneously rotated by the chain 164, and the threading of theshaft 156 in the fixed nuts 160 (FIG. 5) will adjust the height of thecasing 30 and thus adjust the lower limit of the stroke of the shaft 36.

In FIG. 6 of the drawings there is illustrated an electrical systemwhich may be employed with the apparatus of the present invention. Thesystem is designed for patient safety and is compatible with the usual12 volt DC. power generally available in ambulances and other emergencyvehicles. Further, all switches, relays, contacts and the like should beof the hermetically sealed type to comply with explosion-proofrequirements for devices to be operated in an operating roomenvironment.

In FIG. 6 the lines 188 and 190 are connected to a source, for example,a conventional 12-volt battery of an ambulance. These lines arecontrolled by a double pole switch 186. The lower travel limit switch120 is provided with a contact 192 connected to a wire 194. This switchis shown as having an arm 196 normally disengaged from the contact 192and connected by wire 198 to the line wire 188. In connection with thisswitch and other elements of the apparatus, it will be noted in FIG. 6that they have been designated as NO. or N.C. which legends indicate,respectively, that the elements are in normally open or normally closedcondition.

Whereas the lower travel limit switch 120 is normally open, as shown,the upper travel limit switch 126 is normally closed and is adapted tobe opened when the piston reaches its upper limit of movement. Theswitch 126 has a stationary contact 200 normally engaged by a switch arm202 adapted to be opened when the flange 88 contacts with the roller 128at the upper limit of movement of the piston. The contact 200 isconnected to the line wire 190. The switch arm 202 is connected by awire 204 to one terminal of a relay magnet 206; the other end of whichis connected by a wire 208 to which the wire 194 is connected. Thearmature 210 of the relay 206 is adapted to engage a contact 212 towhich the wire 208 is connected.

The switch contact 212 is connected as at 214 to one terminal of each ofthe solenoids 142 and 148. The other terminals of these solenoids areconnected as at 216 to a return wire 218 connected to the line wire 190.Thus the solenoids 142 and 148 are simultaneously energized andsimultaneously de-energized.

The wire 218 is connected to one terminal of the latch solenoid 120, theother terminal of which is connected to a wire 220 leading to a switcharm 222 of the timer 153. This switch arm is normally open and isoperated by the timer to engage a contact 224 connected to a wire 226leading to the line wire 188. The wires 218 and 226 are connected to thetimer 153 so that the latter is constantly energized. This timer isself-resetting as stated above. A switch 186 controls the connection ofthe power lines to lines 188 and 190 within the casing. The switch maybe operated by a handle 194 (FIG. 2) projecting from the casing 30.

OPERATION With the switch 186 open, the valves 138 and 146 will be innormal positions (FIG 1), the lower chamber of the cylinder 32 thuscommunicating with the reservoir 130 through the chamber 140. With thetimer 153 adjusted for the desired nominal period of delay in itsoperation, for example one second, the apparatus may be set in operationby closing the switch 186. With the piston at its lower limit ofmovement, the normally open switch 120 will have been closed byengagement with the flange 82.

Under such conditions, current will flow from line wire 188 through wire198, switch arm 196, contact 192, wire 194, wire 208 and relay 206,thence back to the source through wire 204, the normally closed uppertravel limit switch 126 and line wire 190.

Energization of the relay 206 closes the armature switch 210, and thisestablishes a holding circuit in which current flows through the relay206 and limit switch 126 through wire 188 and relay switch 210. This isimportant since it will be seen that immediately upon the starting ofupward movement of the piston 34, the switch arm 196 will be released tomove to its normally open position as soon as the flange 82 movesupwardly beyond the roller 122 (FIG. 1).

The valves 138 and '146 normally occupy the positions shown in FIG. 1,the lower end of cylinder 32 communicating with the reservoir throughthe port 136 and chamber 140. The closing of the circuit as describedabove through the relay switch 210 provides a holding circuit which willbe maintained after the switch 196 has opened and until the switch 202is opened when the piston 34 reaches its upper limit of movement. Undersuch conditions, current will flow through line wire 188, relay switch,210, wire 214 through solenoids 142 and 148 and thence back to thesource through wires 216 and 218. Energization of the solenoids 142 and148 operates to close the valve 138 and move the valve 146 to the left(FIG; 1) to open the port 144 and close the chamber 150 to the reservoirreturn pipe '134. At this time it will be noted that a circuit throughthe latch solenoid 120 depends on the closing of the timer switch 222,and accordingly the latch 116 will be in released condition ready toengage the flange 88 when the piston 34 reaches its upper limit ofmovement.

The reversing of the positions of the valves 138 and 146 supplies fluidpressure through port 144 to the lower end of the cylinder 32, whereuponthe piston 34 begins its upward movement to release the padded foot 42from the patients chest. When the piston reaches its upper limit ofmovement, the flange 88 will operate the limit switch 126 to open it,thus breaking the circuit through the relay 206, whereupon the relayswitch 210 will open to deenergize the valve solenoids 142 and 148.These valve solenoids then return to the normal positions shown inFIG. 1. However, as upward movement of the piston approaches theposition at which the limit switch 126 will be open, the latch finger116 will snap beneath the flange 88 to hold the piston 34 in its upperlimit of movement.

After the expiration of the time limit for which the timer 153 has beenset, the timer operates to close the switch 222, whereupon current willflow from the line wire 188 through wire 226, switch 222, wire 220 andsole noid 120, and thence back to the source through wire 218 and linewire 190. The latch solenoid 120 thus will be energized and the latchfinger 116 will be released from the flange 88 (FIG. 1). The loading ofthe spring 52 then moves the piston 34 downwardly to cause the resilientfoot 42 to exert a pressure against the patients chest.

The application of resilient force for this purpose is important sinceit is undersirable to exert a positive nonresilient force against thepatients chest. It is also desirable that the loading of the spring beadjustable to vary the resilient force applied to the patients chestaccording to his age and size. For this purpose the spring seat 54 maybe moved downwardly to increase the loading of the spring or upwardly toreduce the spring loading. This loading of the spring 52 is adjustedwhile the apparatus is not in operation and with the piston 34 at itslower limit of movement. The adjustment is accomplished by rotating thewheel 76 to transmit movement through the shaft 60 to the pinions 62 andracks 56.

It will be apparent that immediately after the energization of the latchsolenoid 120 to release the latch finger 116 from the flange 88, thisflange will move below the roller 128 (FIG. 1) whereupon the switch arm202 (FIG. 6) will return to its normally closed position. The circuitthrough the relay 206 will have been opened upon the opening of theswitch arm 202 at the upper limit of piston movement, and the relaycircuit will not be closed when the switch arm 202 returns to itsnormally closed position since the switch arm 196 of the lower travellimit switch 120 will be open.

When the piston 34 reaches its lower limit of movement, the flange 82will engage the roller 122 and close the switch arm 196 to againenergize the relay 206 and energize the valve solenoids 142 and 148 tostart the next upward movement of the piston 34 as described above. Thusthe piston 34 will continue to reciprocate to effect the cardiacmassaging of the patient.

The foregoing operations are carried out with the gear 92 and associatedelements removed from the apparatus, it being apparent that the opentopped bearing 96 permits the instantaneous placing of the shaft 94 inthe bearing and the removal of the shaft therefrom. The gear 92 andassociated elements are used in the event of a failure of power in theapparatus. Should power fail, the shaft 94 is placed in the bearing 96,and with the handle 98 in the upper or dotted line position, theoperator will move the handle downwardly to the solid line position,thus raising the piston 34 to perform the function normally performed byfluid pressure beneath the piston. When the piston reaches the upper endof its stroke, the operator will push the finger piece 102 to releasethe pawl from the teeth of the gear 92, the handle being swung upwardlyto the dotted line position while holding the pawl 100 released from thegear 92. Pushing the button 112 will release the latch 116, and thespring 52 will then perform its normal function of exerting pressureagainst the patient. When the piston reaches its lower limit ofmovement, the operator will release the ratchet 100 and again operatethe handle 98 to lift the shaft 36 and piston 34. Thus the functions ofthe apparatus may be carried out manually in the event of a powerfailure.

The present invention provides for a simple, reliable and portable meansfor closed chest cardiac massage for use in a case of cardiac arrest.The device by its simplicity and size is highly cost-effective as ameans for reducing the requirement for trained medical personnel duringcardiac arrest. The device is small and requires little space and may bequickly set up and placed in automatic operation.

We claim:

1. A closed chest cardiac massage apparatus comprising a reciprocatingmechanism having a padded foot at one end engageable with the patient,means for effecting movement of said foot away from the patient,including a cylinder having a piston therein provided with a piston rodconnected at one end to said padded foot, said means for effectingmovement of said foot away from the patient comprising fluid pressuremeans for supplying fluid pressure to the end of said cylinder towardthe patient, and spring means for effecting movement of said foot intopressure engagement with the patient to produce a cardiac massageeffect.

2. Apparatus according to claim 1 wherein said spring means comprises acompression spring arranged in the other end of said cylinder andengaging said piston, said fluid pressure means developing pressure inexcess of the maximum loading of said spring to effect movement of saidpiston against the loading of said spring.

3. An apparatus according to claim 2 provided with a control mechanismfor said fluid pressure means for admitting pressure to said first namedend of said cylinder when said piston is adjacent thereto, and formaintaining such pressure for a predetermined distance of travel of saidpiston toward said other end of said cylinder and then relieving saidpressure and rendering said spring effective for moving said pistontoward said first named end of said cylinder.

4. Apparatus according to claim 3 provided with a latch automaticallyengageable with said piston rod when said piston has moved saidpredetermined distance toward said other end of said cylinder, and atimer for releasing said latch after the latter has engaged said pistonrod for a predetermined interval of time.

-5. An apparatus according to claim 3 wherein said fluid pressure meanscomprises a motor-pump unit, a reservoir connected to said unit tocontinuously supply a hydraulic fluid thereto, and automatic meansoperable when said piston moves said predetermined distance toward saidother end of said cylinder for opening the first named end thereof tosaid reservoir and for bypassing fluid from the outlet of said pump tosaid reser- 6. Apparatus according to claim 5 wherein said means foropening said first named end of said cylinder to said reservoircomprises a valve biased to open position, and means for closing thesaid valve when said piston has moved to its limit of movement towardsaid first named end of said cylinder.

7. Apparatus according to claim 6 wherein said means for bypassingpumped fluid from said pump to said reservoir comprises a bypass line, adual valve device, and

means for moving such valve to deliver pumped fluid to said first namedend of said cylinder after said piston has reached its limit of movementtoward said first named end of said cyinder and for closingcommunication between said pump and said bypass line, and automaticmeans operable upon movement of said piston said predetermined distancetoward said second named end of said cylinder for opening said firstnamed valve and for reversing the movement of said dual valve device forclosing communication between said pump and said first named end of saidcylinder and for opening communication between said pump and said bypassline.

8. Apparatus according to claim 3 provided with means including anelement carried by said piston rod at the end thereof opposite said footfor adjusting said predetermined travel of said piston toward saidsecond named end of said cylinder.

9. Apparatus according to claim 8 wherein said element carried by saidpiston rod comprises a sleeve mounted on said piston rod for axialmovement therealong, solenoid means energizable for closing said firstnamed valve and opening communication between said pump and said firstnamed end of said cylinder, a circuit for said solenoid means includinga limit switch, said limit switch being biased to closed position andbeing engageable with said element upon the completion of saidpredetermined distance of travel of said piston for opening said circuitwhereby said first named valve opens, said dual valve device beingbiased to a position opening communication between said pump and saidbypass line and closing communication between said pump and saidcylinder whereby, when said circuit is broken, said dual valve deviceWil move to such position.

10. Apparatus according to claim 9 provided with means for limitingmovement of said pressure foot toward References Cited UNITED STATESPATENTS 6/1966 Rand et a1. l285.2 3/1967 Hewson.

L. W. TRAPP, Primary Examiner

